1. Field of the Invention
The present invention relates to an image forming apparatus that forms images by an electro-photographic method, such as a copying machine, a printer, a facsimile apparatus or a multifunction peripheral.
2. Description of the Related Art
A multi-color or full-color electrophotographic image forming apparatus includes a cleaning unit that removes toner remaining on a transfer belt. As a cleaning unit, a configuration in which toner on a transfer belt is scraped with a cleaning blade (a cleaning member) that is in press-contact with the transfer belt has been put into practical use. The toner removed by the cleaning unit is conveyed by a toner conveyance unit to a toner discharge opening that is provided at a downstream side in the toner conveying direction. The downstream side of the toner discharge opening is provided with a toner accommodating container that houses toner. Toner flows from the toner discharge opening of the cleaning unit into an opening that is formed in the toner accommodating container, so that the toner is contained in the toner accommodating container.
A toner accommodating container as mentioned above is known to have a construction in which the toner accommodating container is attachable to and detachable from the apparatus main body so that when the toner accommodating container is full, a user or a service person can replace the container with a new toner accommodating container. Furthermore, a construction is proposed in which when the toner accommodating container is being attached or detached, the opening of the toner accommodating container is closed with a shutter (i.e., an opening-closing member) so that toner will not leak out of the opening.
Japanese Patent Application Laid-Open No. 2002-169441 discusses a toner accommodating container that includes an urging member that urges an opening-closing member in a direction that closes the opening of the toner accommodating container. In this construction, the urging member certainly allows the opening-closing member to close the opening when the toner accommodating container is detached from the apparatus main body.
However, in Japanese Patent Application Laid-Open No. 2002-169441, the urging member of the toner accommodating container always urges the opening-closing member in a direction that closes the opening. Therefore, in the construction discussed in this document, in order to open the opening of the toner accommodating container when attaching the toner accommodating container to the apparatus main body, it is necessary to place the opening-closing member in contact with the cleaning member and move the opening-closing member in a direction that opens the opening portion against the force caused by the urging member. Hence, in the construction discussed in Japanese Patent Application Laid-Open No. 2002-169441, at the time of attaching the toner accommodating container to the apparatus main body, the force of the urging member acts as a reaction force against the force attaching the toner accommodating container to the apparatus main body, giving rise to possibility of reducing the ease of the operation of attaching the toner accommodating container to the apparatus main body.